Answer:
A cladogram is a diagram used to show relations among organisms in cladistics. Cladograms were generated on the basis of DNA and RNA sequencing data, morphological characters and computational phylogenetics.
Cladogram helps to classify organisms on the basis of shared traits between the ancestors and its easy to find related ancestor from cladistics. cladistics also shows evolved characteristics of an organism and how they are related to their ancestors.
Whereas outward appearances cannot show the genetic changes occured in an organism and can provide wrong information about the ancestors.
Hence, Cladogram using DNA is more accurate than using outward appearances.